JPH06163638A - Substrate for arrangement of bump - Google Patents

Abstract

PURPOSE:To effectively thin the thickness in mounting and enable the works such as primary junction, mounting of a semiconductor device, and others to be performed smoothly. CONSTITUTION:This board is arranged so that it can mount a bump 4 on each through hole 6, being equipped with many through holes 6 which are opened according to the disposition pattern of the bumps 4 junctioned with the tips of the leads 3 made on a base film 2, to be connected with a semiconductor chip. The thickness of a board at the peripheral section on the side where the bumps 4 are mounted is made thinner than the thickness of the board at the section where the through hole 6 is opened, so that the opposite section of the base film 2 may be thin. Especially, even if it is a small bump 4, it can be junctioned surely to the tip on base film 2 side of the lead, and thickness in mounting can be effectively thinned.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called TAB tape in which TAB (Tape Automated Bonding), which is one of the mounting techniques for semiconductor elements, has fine metal spheres that serve as bonding bumps arranged in a predetermined arrangement pattern. The present invention relates to a bump array substrate used when transferring to a tip of a lead.

[0002]

2. Description of the Related Art In the TAB method, when lead wiring is performed on an electrode portion of a semiconductor chip, a tip portion of leads (finger leads) formed by patterning on a TAB tape (film carrier) and a semiconductor are formed. This is a method of joining the electrode portion of the chip via a metal projection for joining, that is, a bump. The bumps are attached in advance to the leads on the TAB tape side or the electrode parts of the semiconductor chip, and when the TAB tape and the semiconductor chip are bonded, heating and pressing are performed using a bonding machine.

2 and 3 show examples of the structure of the TAB method and its TAB tape, etc. In the figures, 1 is a semiconductor chip, 2 is a base film of the TAB tape,
It has a device hole 2a in the center thereof. Also,
Reference numeral 3 is a finger lead formed so as to project into the device hole 2a, and 4 is a bump. When bonding the TAB tape and the semiconductor chip 1, the so-called IC bump method shown in FIG. 3A is generally widely used.
In this IC bump method, the bumps 4 are previously formed on the semiconductor chip 1
According to this method, since the semiconductor chip 1 is housed in the device hole 2a formed in the base film 2 of the TAB tape, the thickness after mounting can be reduced. It has features.

On the other hand, the method of forming the bumps 4 on the TAB tape side instead of attaching the bumps 4 to the semiconductor chip 1 side (TAB with bumps) has no risk of damaging the semiconductor chip 1 during the formation of the bumps 4. Since then, it has been widely practiced in recent years. In the mounting using the TAB with bumps, as shown in FIGS. 3 (b) and 3 (c),
There are two cases depending on whether the bump 4 is attached to the front or back side of the TAB tape. Normally, the bump 4 is shown in FIG.
As shown in (b), it is provided on the side opposite to the base film 2. In this case, since the semiconductor chip 1 is not housed in the device hole 2a of the base film 2, the thickness after mounting is smaller than that of the IC bump method (FIG. 3A).
It gets quite thick. Therefore, in order to reduce the mounting thickness, it is possible to attach the bumps 4 to the base film 2 side as shown in FIG.

However, the bump 4 is replaced with the finger lead 3
3 (c), the bumps formed by plating on a flat glass substrate before attachment are transferred to the tip portions of the finger leads 3 when attaching to
The base film 2 on the mounting side of the bump 4 as in the case of
The thickness of the hindrance hinders practical installation. In this case, the thickness of the bumps 4 is set to the base film 2
It is possible to bond the bumps 4 to the finger leads 3 by making the heads of the bumps 4 project above the base film 2.
However, the use of such thick bumps 4 usually leads to the use of a large amount of expensive bump material metal using gold (Au), which in turn raises the cost and increases the thickness of such thick bumps. When the bumps 4 are formed as shown in FIG. 3C, the original purpose of reducing the mounting thickness cannot be achieved.

Further, the present applicant has previously proposed a new method of forming a spherical bump on the lead tip portion of the TAB tape (Japanese Patent Laid-Open No. 3-174737). But,
Also in this method, when the size of the bump is reduced so that the diameter of the bump is smaller than the thickness of the base film, the bump is formed in a shape as shown in FIG. 3C. Will be difficult.

Here, FIG. 4 schematically shows the novel TAB with bumps already proposed by the present applicant and the bonding process with the semiconductor device. In the figure, in the primary bonding step, after the fine metal spheres 4 to be bumps are sucked and fixed onto the through holes of the array substrate 5, they are attached to the tips of the finger leads 3 formed on the TAB base film 2. Joined together. In the secondary bonding step, the finger leads 3 of the TAB tape bumped in the primary bonding step and the electrode portions of the semiconductor chip 1 are aligned and bonded.
The secondary bonding is performed in mounting the semiconductor chip 1, while the primary bonding is performed for manufacturing the bumped TAB. Then, in the primary bonding step, the array substrate 5 for temporarily arraying the fine metal balls 4 to be bumps according to a predetermined pattern is used. Regarding whether or not the fine metal spheres 4 adsorbed on the array substrate 5 are attached to the base film 2 of the TAB tape, the relationship between the array substrate 5 and the size of the bumps 4 and the thickness of the base film 2 is a problem. Become.

FIG. 5 is a diagram for explaining the primary bonding process. FIG. 5A shows a TAB in which the bumps 4 are adsorbed on the through holes 6 of the array substrate 5 and aligned with the upper portions thereof.
The finger lead 3 of the tape is on standby. In the figure, reference numeral 7 denotes a substrate pedestal for depressurizing the through holes 6 of the array substrate 5, and inside the substrate pedestal 7, a depressurizing passage 9 communicating with the through holes 6 is formed. However, the other end of the pressure reducing passage 9 is connected to the pressure reducing suction port 8
Is connected to a decompression device (not shown).

If the bump 4 is larger than the thickness of the base film 2 of the TAB tape, the finger lead 3 is brought close to the bump 4 in the state shown in FIG. 5B, and a bonding tool (not shown) is lowered from above. The bumps 4 can be fixed to the base film 2 side of the finger leads 3 by heating and pressing. However, if the size of the bumps 4 becomes smaller than the thickness of the base film 2, as shown in FIG. 5C, before the finger leads 3 and the bumps 4 come into contact with each other, the end portions of the array substrate 5 are It contacts the base film 2 of the TAB tape. If the base film 2 is set so as to face upward, the mounting of the bumps 4 on the finger leads 3 can be performed without any problem. In this case, the configuration after mounting the semiconductor chip 1 is shown in FIG. ) Type, and it becomes impossible to realize the purpose of reducing the mounting thickness. In other words, T with bump
It is difficult for AB to reduce the amount of bump metal used and to reduce the mounting thickness by any of the conventional methods.

[0010]

The method of attaching the bumps 4 to the finger leads 3 on the TAB tape is as follows.
The inner lead portion of the finger lead 3 is designed to project long into the device hole 2a of the base film 2, or conversely, the TAB tape side is left as it is, and the array substrate 5 and a substrate for receiving the same. The pedestal 7 is formed in such a size that it can be accommodated in the device hole 2a. Therefore, it is easily conceivable to set the relative relationship as shown in FIG. 6 and perform the primary bonding without contact between the array substrate 5 and the base film 2. However, if the tips of the finger leads 3 are lengthened, lead deformation is likely to occur, and there is a risk that the yield of TAB mounting will be significantly reduced, especially when joining is performed by accurately aligning with a fine pitch.

On the other hand, when the array substrate 5 and its substrate pedestal 7 are formed small, in principle, the array substrate 5 should be downsized to the outer limit position of the row of the through holes 6 formed on the array substrate 5. Is possible. Further, practically, the state shown in FIG. 6 cannot be realized unless the array substrate 5 is reduced in size. However, the array substrate 5
If the above is reduced as described above, the size of the end portion 10 of the array substrate 5 cannot be substantially secured, and therefore the array substrate 5 can be stably set on the substrate pedestal 7. Difficult to do. Further, even if the array substrate 5 can be set, if the end portion 10 is short, the reduced pressure suction force is generated in a portion other than the through hole 6 of the array substrate 5,
This extends to a minute gap between the array substrate 5 and the substrate pedestal 7. As a result, when the bumps 4 are adsorbed, the through holes 6 of the array substrate 5 and the gap portion below the array substrate 5 are formed at the same time. However, the bumps 4 are also adsorbed, which causes a problem such as hindering the primary bonding process.

In view of the above-mentioned circumstances, the present invention can reduce the mounting thickness to the same extent as the normal TAB method while using the bumped TAB method, and can perform the primary bonding and the mounting of the semiconductor device. It is an object of the present invention to provide a bump arranging substrate that does not hinder other operations including the above.

[0013]

The bump arranging substrate of the present invention corresponds to a bump arranging pattern to be connected to a semiconductor chip, the bump arranging pattern being bonded to the tips of the leads formed on the base film. Equipped with a large number of through holes,
In the substrate for bump arrangement capable of mounting the bumps on each through hole, the plate thickness of the outer peripheral portion on the side where the bumps are mounted is reduced so that the base film facing portion is thinned, It is made thinner than the plate thickness of the opening portion of the through hole.

Further, in particular, the bump arranging substrate of the present invention is constituted by stacking a plurality of plates having the same arranging pattern and having different peripheral sizes so that their through holes are aligned with each other.

[0015]

According to the present invention, the bump arranging substrate is formed such that the peripheral portion is thinner than the substrate main body portion having the through holes. By setting the difference in thickness between the thick portion and the thin portion to be approximately the same as the thickness of the base film of the TAB tape, even if the size of the bump is extremely small, the device hole of the finger lead is not formed. A spherical bump can be bonded to the side surface without any trouble. Further, since the thin portion of the array substrate spreads in the periphery, it can be set on the substrate pedestal without any trouble, and it is not necessary to form the protruding portion of the finger lead into the device hole for a long time.

The bump arranging substrate according to the present invention can be formed by using metal such as nickel or stainless or ceramics. Etching or machining can be used as a method for providing a difference in plate thickness between the substrate main body portion and its peripheral portion. In the case of forming a through hole, as compared with the case of a normal bump arranging substrate, it becomes difficult to form a small diameter through hole as the plate thickness of the portion where the through hole is formed becomes larger, but a substrate of an integral body. When it is difficult to form the through-holes, it is advantageous to stack a plurality of substrates. In this case, after forming through holes of the same pattern on each substrate to be polymerized, each substrate is polymerized so that the through holes are aligned. By forming a large size of the plurality of substrates to be overlapped with the end portions, the thickness of the peripheral portion can be easily reduced.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a bump arranging substrate according to the present invention will be described below with reference to FIG. In the first embodiment, in order to primary-bond the spherical bumps 4 to the finger leads 3 of the TAB tape used for mounting a semiconductor chip (not shown) having a total of 200 electrodes on the outer periphery of the four sides at a pitch of 140 μm, An array substrate 11 made of stainless steel and having a thickness of 0.2 mm is manufactured.

This array substrate 11 is made by cutting a stainless steel plate having a thickness of 0.2 mm into 15 mm squares, and then cutting the peripheral area of 3.2 m.
By etching the edge portion having a width of m, the thickness is reduced to 0.1 mm to form the thin portion 12. After this, a through hole 6 having an inner diameter of 40 μm is provided at a position close to the inside of the outer peripheral portion of the thick portion in the center.
Are formed at a pitch of 140 μm by an electric discharge machining method. The thickness of the base film 2 of the TAB tape is 100μ.
m. In the present embodiment, the difference in plate thickness between the central portion and the peripheral portion of the array substrate 11 is set to 0.1 mm, which is the same as the thickness of the base film 2, so that the bumps 4 having a relatively small diameter of about 50 μm are formed. Even with respect to this, the primary bonding can be properly and properly performed on the base film 2 side of the finger lead 3 of the TAB tape.

In the above case, if the bump 4 is extremely small,
When the bump 4 is deeply sunk into the through hole 6 and the base film 2 is pressed against the bump 4 temporarily fixed to the through hole 6 from above to make a primary bond, the bump 4 has an opening edge of the through hole 6. The bumps 4 are digging into the area, and the bumps 4 are the array substrate 1
The problem that it becomes difficult to separate from 1 may occur. Therefore, when using the bumps 4 having a diameter of 50 μm or less, it is necessary to set the diameter of the through holes 6 to 30 μm or less as well as the thickness difference between the central portion and the peripheral portion of the array substrate 11. Become.

As described above, in the bump arranging substrate 11 of the present invention, since the thin portion 12 is provided in the peripheral portion,
Substrate pedestal 7 having grooves for vacuum suction formed on its surface
When it is set on the upper side, a pressure leak occurs from its peripheral portion, and further, when the bumps 4 are sucked, the bumps 4 are sucked in the gaps between the bump array substrate 11 and the substrate pedestal 7. It can be completely eliminated. Further, the size of the bump arranging substrate 11 itself is maintained as it is, and the peripheral portion thereof is thinned to effectively prevent the base film 2 of the TAB tape from coming into contact with the bump arranging substrate 11 during the primary bonding. Therefore, the bumps 4 can always be properly bonded to the predetermined positions on the base film 2 side of the finger leads 3 of the TAB tape.

In the second embodiment of the bump arranging substrate according to the present invention, the bump arranging substrate for bonding the spherical bumps to the TAB tape having the same pattern as in the first embodiment is:
15 mm square nickel plate (A substrate) with a thickness of 40 μm,
8 mm square nickel plate (B substrate) with a thickness of 40 μm and 8.6 mm square stainless steel plate (C substrate) with a thickness of 50 μm
It is manufactured by polymerizing three substrates. Through holes for mounting bumps are formed in the central portions of the A substrate, the B substrate, and the C substrate in accordance with the same arrangement pattern. The A substrate and the B substrate are formed by the elect forming method. Diameter of 30μ at the same time
200 m through holes are formed. Further, in the C substrate, 200 through holes having a diameter of 40 μm are similarly formed by etching. As in the case of the first embodiment, these through holes are arranged such that 50 holes are arranged on each of the four sides at a pitch of 140 μm. Then, the A substrate, the B substrate, and the C substrate are polymerized in this order and attached to each other with an adhesive.

In the bump arranging substrate according to the second embodiment, the peripheral portion has a plate thickness of 40 μm, and the through hole opening portion has a plate thickness of more than 140 μm. The size of the through holes of the C substrate is made larger than the through holes of the A substrate and the B substrate, respectively.
This is because in order to form the through holes with high accuracy by etching, the diameter of the stainless steel plate having a thickness of 50 μm is limited to 40 μm. Even in this case, the diameter of the A substrate is 30 when the bumps are picked up.
Since the through hole of μm is used, no inconvenience occurs. According to the second embodiment, even with a small bump having a diameter of about 35 μm, proper and reliable primary bonding of the bump to the finger lead of the TAB tape can be guaranteed.

In the third embodiment of the bump arranging substrate according to the present invention, a substrate having a thickness of 0.16 mm and a size of 15 mm square is formed by using a boride-based ceramic (trade name: Cera-Borex) which is one of conductive ceramics. Is produced. Further, along the periphery thereof, a 3.2 mm wide portion is polished to 0.1 mm to be thin. In this case, it is necessary to set the polishing width in consideration of the radius of the corners because the sharp corners cannot be obtained by the thinning process by polishing. In addition, since the radius of the corner portion is likely to be large during polishing, it is preferable to perform electric discharge machining after polishing. In this way, the bump array substrate having a stepped portion in the peripheral portion thereof has a through hole having a diameter of 30 μm in the thick portion in the center.
200 pieces are formed at a pitch of 0 μm. According to the third embodiment, the spherical bump having a diameter of about 65 μm can be primary-bonded properly and reliably to the finger lead of the TAB tape.

[0024]

As described above, according to the present invention, the TAB
Even small bumps can be reliably bonded to the base film side of the finger leads when the primary bonding of the bumps to the tape is performed, and when this TAB tape is applied to semiconductor mounting, the mounting thickness is effective. Decreased to
It has the advantage that it can be as thin as the conventional IC bump method.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a usage state of a bump array substrate according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing a structural example of a TAB tape according to a conventional bump array substrate.

FIG. 3 is a diagram showing various conventional TAB methods with different bump positions.

FIG. 4 is a TA performed using a conventional bump array substrate.
It is a perspective view which shows the manufacturing process of B tape.

FIG. 5 is a vertical cross-sectional view showing a mode of bump primary bonding performed using a conventional bump arranging substrate.

FIG. 6 is a vertical cross-sectional view showing another mode of bump primary bonding performed using a conventional bump arranging substrate.

[Explanation of symbols]

 1 semiconductor chip 2 base film 3 finger leads 4 bumps 6 through holes 7 substrate pedestal 8 decompression suction port 9 decompression passage 11 array substrate 12 thin portion

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[Procedure amendment]

[Submission date] January 25, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Detailed explanation of the invention

[Correction method] Change

[Correction content]

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called TAB tape in which TAB (Tape Automated Bonding), which is one of the mounting techniques for semiconductor elements, has fine metal spheres that serve as bonding bumps arranged in a predetermined arrangement pattern. The present invention relates to a bump array substrate used when transferring to a tip of a lead.

[0002]

2. Description of the Related Art In the TAB method, when lead wiring is performed on an electrode portion of a semiconductor chip, a tip portion of leads (finger leads) formed by patterning on a TAB tape (film carrier) and a semiconductor are formed. This is a method of joining the electrode portion of the chip via a metal projection for joining, that is, a bump. The bumps are attached in advance to the leads on the TAB tape side or the electrode parts of the semiconductor chip, and when the TAB tape and the semiconductor chip are bonded, heating and pressing are performed using a bonding machine.

2 and 3 show examples of the structure of the TAB method and its TAB tape, etc. In the figures, 1 is a semiconductor chip, 2 is a base film of the TAB tape,
It has a device hole 2a in the center thereof. Also,
Reference numeral 3 is a finger lead formed so as to project into the device hole 2a, and 4 is a bump. When bonding the TAB tape and the semiconductor chip 1, the so-called IC bump method shown in FIG. 3A is generally widely used.
In this IC bump method, the bumps 4 are previously formed on the semiconductor chip 1
According to this method, since the semiconductor chip 1 is housed in the device hole 2a formed in the base film 2 of the TAB tape, the thickness after mounting can be reduced. It has features.

On the other hand, the bumps should be TA instead of the semiconductor chip side.
The method of forming on the B tape side (TAB with bumps) has been widely used in recent years because there is no risk of damaging a semiconductor chip during the formation of bumps. In the mounting using such a bumped TAB, as shown in FIG.
As shown in (c), there are two cases depending on whether the bump 4 is attached to the front or back side of the TAB tape. Usually, the bumps 4 are provided on the side opposite to the base film 2, as shown in FIG. In this case, since the semiconductor chip 1 is not housed in the device hole 2a of the base film 2, the thickness after mounting becomes considerably thicker than that of the IC bump method (FIG. 3A).
Therefore, in order to reduce the mounting thickness, it is possible to attach the bumps 4 to the base film 2 side as shown in FIG.

However, when the bumps are attached to the finger leads, the bumps formed by plating on a flat glass substrate are transferred to the tip portions of the finger leads. In the usual method, the base on the side where the bumps are attached is mounted. The thickness of the film becomes an obstacle, making it virtually impossible to attach. In this case, if the bumps are made thicker than the base film so that the heads of the bumps project above the base film, it is possible to bond the bumps to the finger leads themselves. is there. However, the use of such thick bumps usually requires the use of a large amount of expensive bump material metal, which uses gold (Au), which in turn increases the cost and increases the thickness of such thick bumps. 3C is formed, the original purpose of reducing the mounting thickness cannot be achieved.

Further, the present applicant has previously proposed a new method of forming a spherical bump on the lead tip portion of the TAB tape (Japanese Patent Laid-Open No. 3-174737). But,
Also in this method, when the size of the bump is reduced so that the diameter of the bump is smaller than the thickness of the base film, the bump is formed in a shape as shown in FIG. 3C. Will be difficult.

Here, FIG. 4 schematically shows the novel TAB with bumps already proposed by the present applicant and the bonding process with the semiconductor device. In the figure, in the primary bonding step, the fine metal spheres 4 to be bumps are sucked onto the through holes of the array substrate 5 and temporarily fixed, and then the TAB base film 2 is formed.
The tip ends of the finger leads 3 formed above are collectively joined. In the secondary bonding step, the finger leads 3 of the TAB tape bumped in the primary bonding step and the electrode portions of the semiconductor chip 1 are aligned and bonded. This secondary bonding is carried out in the mounting of the semiconductor chip, while the primary bonding is carried out for the production of the TAB with bumps. Then, in the primary bonding step, the array substrate 5 for temporarily arraying the fine metal balls 4 to be bumps according to a predetermined pattern is used. The fine metal balls 4 adsorbed on the array substrate 5 are the base film 2 of the TAB tape.
Whether or not it is attached to
The relationship between the size of the bump 4 and the thickness of the base film 2 poses a problem.

FIG. 5 is a diagram for explaining the primary bonding process. FIG. 5A shows a TAB in which the bumps 4 are adsorbed on the through holes 6 of the array substrate 5 and aligned with the upper portions thereof.
The finger lead 3 of the tape is on standby. In the figure, 7 is a substrate pedestal for depressurizing the through holes 6 of the array substrate 5, and this substrate pedestal 7
A pressure reducing passage 9 communicating with the through hole 6 is formed in the inside of the pressure reducing passage 9, and the other end of the pressure reducing passage 9 is connected to a pressure reducing device (not shown) via a pressure reducing suction port 8.

If the bump 4 is larger than the thickness of the base film 2 of the TAB tape, the finger lead 3 is brought close to the bump 4 in the state shown in FIG. 5B, and a bonding tool (not shown) is lowered from above. The bumps 4 can be fixed to the base film 2 side of the finger leads 3 by heating and pressing. However, if the size of the bumps 4 becomes smaller than the thickness of the base film 2, as shown in FIG. 5C, before the finger leads 3 and the bumps 4 come into contact with each other, the end portions of the array substrate 5 are It contacts the base film 2 of the TAB tape. If the base film 2 is set so as to face upward, the mounting of the bumps 4 on the finger leads 3 can be performed without any trouble. In this case, the configuration after mounting the semiconductor chip 1 is shown in FIG. ) Type, and it becomes impossible to realize the purpose of reducing the mounting thickness. In other words, T with bump
It is difficult for AB to reduce the amount of bump metal used and to reduce the mounting thickness by any of the conventional methods.

[0010]

The method of attaching the bumps to the base film side of the finger leads on the TAB tape is to design the tip ends of the inner leads of the finger leads to project into the device hole for a long time, or conversely. The relative relationship as shown in FIG. 6 should be realized by making the array substrate and the array substrate support that receives it small enough to fit in the device hole without changing the TAB tape side. Is easily thought of. However, if the tips of the finger leads 3 are lengthened, lead deformation is likely to occur, and there is a risk that the yield of TAB mounting will be significantly reduced, especially when joining is performed by accurately aligning with a fine pitch.

On the other hand, when the array substrate and its pedestal are formed small, it is possible in principle to reduce the size to the outside of the through hole array formed on the array substrate. And, in reality, it is difficult to realize the state of FIG. 6 by this means unless a substrate and a pedestal that are reduced to the limit are used. However, the array substrate 5
If the above is reduced as described above, the size of the end portion 10 of the array substrate 5 cannot be substantially secured, and therefore the array substrate 5 can be stably set on the substrate pedestal 7. Difficult to do. Further, even if the array substrate 5 can be set, if the end portion 10 is short, the reduced pressure suction force is generated in a portion other than the through hole 6 of the array substrate 5,
This extends to a minute gap between the array substrate 5 and the substrate pedestal 7. As a result, when the bumps 4 are adsorbed, the through holes 6 of the array substrate 5 and the gap portion below the array substrate 5 are formed at the same time. However, the bumps 4 are also adsorbed, which causes a problem such as hindering the primary bonding process.

In view of the above-mentioned circumstances, the present invention can reduce the mounting thickness to the same extent as the normal TAB method while using the bumped TAB method, and can perform the primary bonding and the mounting of the semiconductor device. It is an object of the present invention to provide a bump arranging substrate that does not hinder other operations including the above.

[0013]

The bump arranging substrate of the present invention corresponds to a bump arranging pattern to be connected to a semiconductor chip, the bump arranging pattern being bonded to the tips of the leads formed on the base film. Equipped with a large number of through holes,
In the substrate for bump arrangement capable of mounting the bumps on each through hole, the plate thickness of the outer peripheral portion on the side where the bumps are mounted is reduced so that the base film facing portion is thinned, It is made thinner than the plate thickness of the opening of the through hole, or is formed by stacking a plurality of plates having the same array pattern and different peripheral sizes so that the through holes are aligned with each other. This is a substrate for bump arrangement.

[0014]

According to the present invention, the bump arranging substrate is formed such that the peripheral portion is thinner than the substrate main body portion having the through holes. By setting the difference in thickness between the thick portion and the thin portion to be approximately the same as the thickness of the base film of the TAB tape, even if the size of the bump is extremely small, the device hole of the finger lead is not formed. A spherical bump can be bonded to the side surface without any trouble. Further, since the thin portion of the array substrate spreads in the periphery, it can be set on the substrate pedestal without any trouble, and it is not necessary to form the protruding portion of the finger lead into the device hole for a long time.

The bump arranging substrate according to the present invention can be formed by using metal such as nickel or stainless or ceramics. Etching or machining can be used as a method for providing a difference in plate thickness between the substrate main body portion and its peripheral portion. In the case of forming a through hole, as compared with the case of a normal bump arranging substrate, it becomes difficult to form a small diameter through hole as the plate thickness of the portion where the through hole is formed becomes larger, but a substrate of an integral body. When it is difficult to form the through-holes, it is advantageous to stack a plurality of substrates. In this case, after forming through holes of the same pattern on each substrate to be polymerized, each substrate is polymerized so that the through holes are aligned. By forming a large size of the plurality of substrates to be overlapped with the end portions, the thickness of the peripheral portion can be easily reduced.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a bump arranging substrate according to the present invention will be described below with reference to FIG. In the first embodiment, in order to primary-bond the spherical bumps 4 to the finger leads 3 of the TAB tape used for mounting a semiconductor chip (not shown) having a total of 200 electrodes on the outer periphery of the four sides at a pitch of 140 μm, An array substrate 11 made of stainless steel and having a thickness of 0.2 mm is manufactured.

This arraying substrate 11 is formed by cutting a stainless steel plate having a thickness of 0.2 mm into 15 mm squares, and then cutting the periphery by 3.2 m.
By etching the edge portion having a width of m, the thickness is reduced to 0.1 mm to form the thin portion 12. After this, a through hole 6 having an inner diameter of 40 μm is provided at a position close to the inside of the outer peripheral portion of the thick portion in the center.
Are formed at a pitch of 140 μm by an electric discharge machining method. The thickness of the base film 2 of the TAB tape is 100μ.
m. In the present embodiment, the difference in plate thickness between the central portion and the peripheral portion of the array substrate 11 is set to 0.1 mm, which is the same as the thickness of the base film 2, so that the bumps 4 having a relatively small diameter of about 50 μm are formed. Even with respect to this, the primary bonding can be properly and properly performed on the base film 2 side of the finger lead 3 of the TAB tape.

In the above case, if the bump 4 is extremely small,
When the bump 4 is deeply sunk into the through hole 6 and the base film 2 is pressed against the bump 4 temporarily fixed to the through hole 6 from above to make a primary bond, the bump 4 has an opening edge of the through hole 6. The bumps 4 are digging into the area, and the bumps 4 are the array substrate 1
The problem that it becomes difficult to separate from 1 may occur. Therefore, when using the bumps 4 having a diameter of 50 μm or less, it is necessary to set the diameter of the through holes 6 to 30 μm or less as well as the thickness difference between the central portion and the peripheral portion of the array substrate 11. Become.

As described above, in the bump arranging substrate 11 of the present invention, since the thin portion 12 is provided in the peripheral portion,
Substrate pedestal 7 having grooves for vacuum suction formed on its surface
When it is set on the upper side, a pressure leak occurs from its peripheral portion, and further, when the bumps 4 are sucked, the bumps 4 are sucked in the gaps between the bump array substrate 11 and the substrate pedestal 7. It can be completely eliminated. Further, the size of the bump arranging substrate 11 itself is maintained as it is, and the peripheral portion thereof is thinned to effectively prevent the base film 2 of the TAB tape from coming into contact with the bump arranging substrate 11 during the primary bonding. Therefore, the bumps 4 can always be properly bonded to the predetermined positions on the base film 2 side of the finger leads 3 of the TAB tape.

In the second embodiment of the bump arranging substrate according to the present invention, the bump arranging substrate for bonding the spherical bumps to the TAB tape having the same pattern as in the first embodiment is
15 mm square nickel plate (A plate) with a thickness of 40 μm, 8 mm square nickel plate (B plate) with a thickness of 40 μm, and a thickness of 5
It is manufactured by polymerizing 3 substrates of 0 μm and 8.6 mm square stainless steel plate (C plate). Through holes for mounting the bumps are formed in the central portions of the A plate, the B plate, and the C plate in accordance with the same arrangement pattern.
When the A plate and the B plate are formed by the elect forming method, 200 through holes each having a diameter of 30 μm are simultaneously formed.
Individually formed. For C plate, the diameter is 4 by etching.
Similarly, 200 0 μm through holes are formed. The arrangement of these through holes is 140 μm, as in the case of the first embodiment.
Fifty pieces are arranged on each of the four sides at a pitch. Then, the A plate, the B plate, and the C plate are polymerized in this order and attached to each other with an adhesive.

In the bump arranging substrate according to the second embodiment, the peripheral portion has a plate thickness of 40 μm, and the through hole opening portion has a plate thickness of more than 140 μm. The size of the through holes of the C plate is made larger than the through holes of the A plate and the B plate. The reason for forming the through holes with high accuracy by etching is that the thickness of the stainless steel plate having a thickness of 50 μm is 40 μm. This is the limit of the diameter. Even in this case, since a through hole having a diameter of 30 μm in the A plate is used when the bump is adsorbed, no inconvenience occurs. According to the second embodiment, even with a small bump having a diameter of about 35 μm, proper and reliable primary bonding of the bump to the finger lead of the TAB tape can be guaranteed.

In the third embodiment of the bump arranging substrate according to the present invention, a substrate having a thickness of 0.16 mm and a size of 15 mm square is formed by using a boride-based ceramic (trade name: Cera-Borex) which is one of conductive ceramics. Is produced. Further, along the periphery thereof, a 3.2 mm wide portion is polished to 0.1 mm to be thin. In this case, it is necessary to set the polishing width in consideration of the radius of the corners because the sharp corners cannot be obtained by the thinning process by polishing. In addition, since the radius of the corner portion is likely to be large during polishing, it is preferable to perform electric discharge machining after polishing. In this way, the bump array substrate having a stepped portion in the peripheral portion thereof has a through hole having a diameter of 30 μm in the thick portion in the center.
200 pieces are formed at a pitch of 0 μm. According to the third embodiment, the spherical bump having a diameter of about 65 μm can be primary-bonded properly and reliably to the finger lead of the TAB tape.

[0023]

As described above, according to the present invention, the TAB
Even small bumps can be reliably bonded to the base film side of the finger leads when the primary bonding of the bumps to the tape is performed, and when this TAB tape is applied to semiconductor mounting, the mounting thickness is effective. Decreased to
It has the advantage that it can be as thin as the conventional IC bump method.

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FIG. 1 is a vertical cross-sectional view showing a usage state of a bump array substrate according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing a structural example of a TAB tape.

FIG. 3 is a diagram showing various TAB methods.

FIG. 4 is a diagram for explaining a method of manufacturing a TAB tape with bumps and a semiconductor mounting method using the TAB tape.

FIG. 5 is a vertical cross-sectional view showing a mode of bump primary bonding performed using a conventional bump arranging substrate.

FIG. 6 is a vertical cross-sectional view showing another mode of bump primary bonding performed using a conventional bump arranging substrate.

[Explanation of reference symbols] 1 semiconductor chip 2 base film 3 finger leads 4 bumps 6 through holes 7 substrate pedestal 8 decompression suction port 9 decompression passage 11 array substrate 12 thin portion

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[Figure 5]

Claims (2)

[Claims] 1. A plurality of through holes are provided corresponding to an array pattern of bumps to be connected to a semiconductor chip, the bumps being bonded to the tips of leads formed on a base film. In the substrate for bump arrangement capable of mounting the bumps on, the plate thickness of the outer peripheral portion on the side on which the bumps are mounted is set so as to reduce the thickness of the base film facing portion. A bump array substrate characterized by being made thinner than the opening portion. 2. The bump arranging substrate according to claim 1, wherein the substrate is formed by stacking a plurality of plates having the same arrangement pattern and having different peripheral sizes so that their through holes are aligned with each other.